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Tinnitus Defined

Tinnitus (pronounced "tin-it-tus") is an abnormal
noise in the ear (note that it is not an "itis" -- which means inflammation). Tinnitus is common -- nearly 36 million Americans have constant
tinnitus and more than half of the normal population has intermittent tinnitus. Another way to summarize this is that about 10-15% of the entire population has some type of constant tinnitus, and about 20% of these people (i.e. about 1% of the population) seek medical attention (Adjamian et al, 2009). Similar statistics are found in England (Dawes et al, 2014) and Korea (Park and Moon, 2014).

The prevalence of tinnitus depends on the questions you ask. Nemholt et al (2019) reported that the prevalence of "any tinnitus" was 66.9% in Danish children aged 10-16. We believe them -- it just shows you get what you ask for. This means that standardized questions are necessary to compare apples to apples.

Curiously, in the US, only 6.6% of Asian Americans report "any tinnitus" (Choi et al, 2020). It is puzzling that Asian americans report about a third of the tinnitus that most populations do (including Korea), and also a 10th of tinnitus of Danish Children. With this wide variability in reports, it would seem that these numbers are pretty fuzzy.

About six percent of the general population has what they consider to be "severe" tinnitus. That is a gigantic number of people ! Tinnitus is more common with advancing age. In a large study of more than 2000 adults aged 50 and above, 30.3%
reported having experienced tinnitus, with 48% reporting symptoms in both ears.
Tinnitus had been present for at least 6 years in 50% of cases, and most (55%)
reported a gradual onset. Tinnitus was described as mildly to extremely annoying
by 67%.(Sindhusake et al. 2003)

Tinnitus can come and go, or be continuous. It can sound like a low roar, or
a high pitched ring. Tinnitus may be in both ears or just in one ear. Seven
million Americans are so severely affected that they cannot lead normal lives.

The most common types of tinnitus are ringing or hissing ringing, whistling
(high pitched hissing) and roaring (low-pitched hissing). Some persons hear
chirping, screeching, or even musical sounds.

Note however that tinnitus nearly always
consists of fairly simple sounds -- for example, hearing someone talking that
no one else can hear would not ordinarily be called tinnitus -- this would be
called an auditory hallucination. Musical hallucinations in patients without psychiatric disturbance is most often described in older persons, years after hearing loss.

Another way of splitting up tinnitus is into objective and subjective. Objective tinnitus can be heard by the examiner. Subjective cannot. Practically, as there is only a tiny proportion of the population with objective tinnitus, this method of categorizing tinnitus is rarely of any help. It seems to us that it should be possible to separate out tinnitus into inner ear vs everything else using some of the large array of audiologic testing available today. For example, it would seem to us that tinnitus should intrinsically "mask" sounds of the same pitch, and that this could be quantified using procedures that are "tuned" to the tinnitus.

Epidemiology of Tinnitus:

Distribution of Persons with tinnitus

Population

Percent with Tinnitus

Percent with Hearing Loss

Reference

General

4-15

Moller, 2007

"pediatric"

22%

Chan et al, 2017

Older than 50

20%

Moller, 2007

65-70

12%

35%

Adams et al, 1999

With respect to incidence (the table above is about prevalence), Martinez et al (2015) reported that there were 5.4 new cases of tinnitus per 10,000 person-years in England. We don't find this statistic much use as tinnitus is highly prevalent in otherwise normal persons. It seems to us that their study is more about how many persons with tinnitus were detected by the health care system -- and that it is more a study of England's health care system than of tinnitus.

Chan et al (2017) compared pediatric to adult tinnitus, and stated that "This study distinguishes pediatric tinnitus from adult tinnitus in terms of lower association with underlying hearing loss, lower likelihood of reported anxiety, and higher likelihood of improvement and resolution. " So it is good to be young.

Accompaniments of tinnitus (pun intended)

Tinnitus is commonly accompanied by hearing
loss, and roughly 90% of persons with chronic tinnitus have some form of hearing loss (Davis and Rafaie, 2000; Lockwood et al, 2002). On the other hand, only about 30-40% of persons with hearing loss develop tinnitus. According to Park and Moon (2004), hearing impairment roughly doubles the odds of having tinnitus, and triples the odds of having annoying tinnitus.

Less commonly, tinnitus may be accompanied by hyperacusis (an abnormal sensitivity
to sound).

Structures of the ear. Most tinnitus is due to damage to the cochlea (#9 above)

Henry et al (2005) reported that noise was an associated factor for 22% of cases, followed by head and neck injury (17%), infections and neck illness (10%), and drugs or other medical conditions (13%). The rest of their patients could not identify an event.

Park and Moon (2004) reported the odds ratio for tinnitus according to many factors. They examined results from 10,061 Koreans.

Thus it can see that there are numerous factors that are weakly correlated with tinnitus, and that hearing impairment is the most strongly associated. It is surprising that TMJ's correlation is nearly as high as hearing impairment, and more than depression or stress. Other studies have similar results (Lee et al, 2016)

It is very well accepted that tinnitus often is "centralized" -- while it is usually initiated with an inner ear event, persistent tinnitus is associated with changes in central auditory processing (Adjamian et al, 2009). Sometimes this idea is used to put forth a "therapeutic nihilism" -- suggesting that fixing the "cause" -- i.e. inner ear disorder -- will not make the tinnitus go away. This to us seems overly simplistic -- while it is clear that the central nervous system participates in perception of sounds, and thus must be a participant in the "tinnitus" process, we think that it is implausible that in most cases that there is not an underlying "driver" for persistent tinnitus.

Supporting the idea that central reorganization is overestimated as "the" cause of tinnitus, a recent study by Wineland et al showed no changes in central connectivity of auditory cortex or other key cortical regions (Wineland et al, 2012). Considering other parts of the brain, Ueyama et al (2013) reported that there was increased fMRI activity in the bilateral rectus gyri, as well as cingulate gyri correlating with distress. Loudness was correlated with values in the thalamus, bilateral hippocampus and left caudate. In other words, the changes in the brain associated with tinnitus seem to be associated with emotional reaction (e.g. cingulate), and input systems (e.g. thalamus). There are a few areas whose role is not so obvious (e.g. caudate). This makes a more sense than the Wineland result, but of course, they were measuring different things. MRI studies related to audition or dizziness must be interpreted with great caution as the magnetic field of the MRI stimulates the inner ear, and because MRI scanners are noisy.

Although mitochondrial DNA variants are thought to predispose to hearing loss, a study of polish individuals by Lechowicz et al, reported that "there are no statistically significant differences in the prevalence of tinnitus and its characteristic features between HL patients with known HL mtDNA variants and the general Polish population." This would argue against mitochondrial DNA variants as a cause of tinnitus, but the situation might be different in other ethnic groups.

Another way to look at it is to look at the areas of the body that can initiate tinnitus.

Ear disorders as a cause of tinnitus

Most tinnitus comes from damage to the inner ear, specifically the cochlea (the snail like thing on the right of figure 1, labeled '9').

Patients with Meniere's disease often describe a low pitched tinnitus resembling a hiss or a roar. This is quite logical as Meniere's affects large pieces of the cochlea, rather than just a localized area that might cause ringing. Somewhat contrary to this assertion, Perez-Carpena et al (2019) said that " The type of tinnitus in Meniere's Disease ranged from pure tones to noise-like tinnitus (white, brown and pink noise). ", or in other words, that anything goes. We are dubious that this is true.

Loud noise is the leading cause of damage to the inner ear. Most patients with noise trauma describe a whistling tinnitus (Nicholas-Puel et al,. 2002). In a large study of tinnitus, avoidance of occupational noise was one of two factors most important in preventing tinnitus (Sindhusake et al. 2003). The other important factor was the rapidity of treating ear infections.

Advancing age is often accompanied by inner ear damage and tinnitus. (Sindhusake et al. 2003)

Patients with head or neck injury may have
particularly loud and disturbing tinnitus (Folmer and Griest, 2003). Tinnitus due to neck injury is the most common type of "somatic tinnitus". Somatic tinnitus means that the tinnitus is coming from something other than the inner ear. Tinnitus from a clear cut inner ear disorder frequently changes loudness or pitch when one simply touches the area around the ear. This is thought to be due to somatic modulation of tinnitus. We have encountered patients who have excellent responses to cervical epidural steroids, and in persons who have both severe tinnitus and significant cervical nerve root compression, we think this is worth trying as treatment.

Some persons with severe TMJ (temporomandibular joint) arthritis have severe tinnitus. Generally these persons say that there is a "screeching" sound. This is another somatic tinnitus. TMJ is extremely common -- about 25% of the population. The exact prevalence of TMJ associated tinnitus is not established, but presumably it is rather high too. Having TMJ increases the odds that you have tinnitus too, by about a factor of 1.6-3.22 (Park and Moon, 2014; Lee et al, 2016). This is the a large risk factor for tinnitus, similar to the risk from hearing loss (see table above).

It is also very common for jaw opening to change the loudness or frequency of tinnitus. This is likely a variant of somatic modulation of tinnitus (see above). The sensory input from the jaw evidently interacts with hearing pathways. The muscles that open the jaw are innervated by the same nerve, the motor branch of 5, that controls the tensor tympani in the ear. In other words, changing tension in the jaw may also change muscle tension in the ear.

Tinnitus arises more rarely from injury to the brainstem (Lanska et al, 1987), and extremely rarely, to the brain itself (e.g. palinacusis).

We have encountered a patient with musical hallucination type tinnitus due to brainstem injury where they were transiently deaf, due to a midbrain injury. This is presumably a form of Charles Bonnet.

Tinnitus is rarely caused by brain disorders. In our experience, this is usually in persons who have strokes in auditory cortex (i.e. temporal lobe) on both sides. This is again presumably a form of Charles Bonnet.

Paquette et al (2017) reported a prospective study of 166 patients who had brain surgery involving removal of the medial temporal lobe. The prevalence of tinnitus increased from approximately from 10 to 20% post surgery. This study did not include a control -- a natural question would be -- suppose a different part of the brain were removed. One would also think that drilling of the skull from any source might increase tinnitus. We are presently dubious that the medial temporal lobe suppresses tinnitus.

Tinnitus can be associated with Basilar Artery Migraine (BAM), and also tinnitus can be more bothersome when one is having a migraine (Volcy et al, 2005), like sound and light and smells.

Tinnitus can occur as a sleep disorder - -this is called the "exploding head syndrome". This most often occurs while falling asleep or waking up. It is a tremendously loud noise. Some theorize that this syndrome is due to a brief seizure in auditory cortex. It is not dangerous.(Green 2001; Palikh and Vaughn 2010).
Logically, anticonvulsants might be useful for treatment.

In pulsatile tinnitus, people hear something resembling their heartbeat in their ear. Click on the link above for more details.

Drug induced tinnitus

In our opinion, people are very quick to blame drugs for their tinnitus, but it is rare that this is borne out.

Many medications also can cause tinnitus (see list below). Generally this is
thought to arise from their effect on the cochlea (inner ear).

Drugs that commonly cause or increase tinnitus -- these are largely ototoxins.

NSAIDS (motrin, naproxen, relafen, etc)

aspirin and other salicylates

Lasix and other "loop" diuretics

"mycin" antibiotics such as vancomycin (but rarely macrolides
such as azithromycin)

quinine and related drugs

Chemotherapy such as cis-platin

Antidepressants are occasionally associated with tinnitus (Robinson, 2007). For example, Tandon (1987) reported that 1% of those taking imiprimine complained of tinnitus. In a double-blind trial of paroxetine for tinnitus, 3% discontinued due to a perceived worsening of tinnitus (Robinson, 2007). There are case reports concerning tinnitus as a withdrawal symptom from Venlafaxine and sertraline (Robinson, 2007). In our clinical practice, we have occasionally encountered patients reporting worsening of tinnitus with an antidepressant, generally in the SSRI family.

Often people bring in very long lists of medications that have been reported, once or twice, to be associated with tinnitus. This unfortunate behavior makes it very hard to care for these patients -- as it puts one into an impossible situation where the patient is in great distress but is also unwilling to attempt any treatment. Specialists who care for patients with ear disease, usually know very well which drugs are problems (such as those noted above), and which ones are nearly always safe.

Malingering of Tinnitus and psychogenic tinnitus.

As tinnitus is essentially subjective, malingering of tinnitus as well as psychological causes of tinnitus is certainly possible. In fact, auditory hallucinations (such as hearing voices) are common in schizophrenia.

In malingering, a person claims to have tinnitus (or more tinnitus), in an attempt to gain some benefit (such as more money in a legal case). See this page concerning malingering of hearing symptoms.

There is a high correlation between anxiety depression and the annoyance/severity of tinnitus (Pinto et al, 2014).

Miscellaneous causes of Tinnitus

Fibromyalgia is often accompanied by tinnitus (Cil et al, 2020). This is not surprising as both tinnitus and fibromyalgia are essentially diagnosed from symptoms alone.

Microvascular compression may sometimes cause tinnitus. According to Levine (2006) the quality is similar to a "typewriter", and it is fully suppressed by carbamazepine. It seems to us that response to carbamazepine is not a reliable indicator of microvascular compression as this drug stabilizes nerves and lowers serum sodium. Nevertheless, this quality of tinnitus probably justifies a trial of oxcarbamazine (a less toxic version of carbamazepine).

Schecklmann et al (2014) suggested that tinnitus is associated with alterations in motor cortex excitability, by pooling several studies, and reported that there are differences in intracortical inhibition, intra-cortical facilitation, and cortical silent period. We doubt that this means that motor cortex excitability causes tinnitus, but rather we suspect that these findings reflect features of brain organization that may predispose certain persons to develop tinnitus over someone else.

Persons with tinnitus
should be seen by a physician expert in ear disease, usually an otologist or
a neurotologist.

General ear exam

There should be an examination of the ears with an otoscope. Wax should be removed, and the examiner should note whether the ear drum is intact, inflamed, scarred, or whether it is moving.

The eyes should be examined for papilloedema (swelling of a portion of the
back of the eye called the "optic disk") as increased intracerebral
pressure can cause tinnitus. Because papilloedema is so rare, and tinnitus is so common, it is very unusual to find this dangerous condition.

The TMJ joints of the jaw should be checked as about 28% of persons with TMJ
syndrome experience tinnitus. TMJ is very common too.

Middle Ear Exam

Inspection of the eardrum may sometimes demonstrate subtle movements due to
contraction of the tensor tympani (Cohen and Perez, 2003). Tensor tympani myoclonus causes
a thumping. Another muscle, the stapedius, can also make higher pitched sounds. See this page for more. Opening or closing of the eustachian tube causes a clicking. The best way to hear "objective tinnitus" from the middle ear is simply to have an examiner with normal hearing put their ear up next to the patient. Stethoscopes favor low frequency sounds and may not be very helpful.

Type of middle ear tinnitus

Sound

Ear Drum

Tensor tympani

Thump, inaudible to examiner

Indentation

Stapedius

Tick, can be heard by examiner

Nothing

ETD

Click, can be heard by examiner

Nothing

Stapedius
and Tensor Tympani Muscles

Cartoon of the middle ear showing muscles that attach to ossicles (ear bones), and ear drum. The stapedius is attached to the stapes (of course -- horseshoe object above), while the tensor tympani is attached to the ear drum. While useful, be aware that there are multiple errors in this illustration from Loyola Medical School. With permission, from: http://www.meddean.luc.edu/lumen/meded/grossanatomy/dissector/mml/images/stap.jpg

Recommended Laboratory testing for tinnitus:

Based on tests, tinnitus can be separated into categories of cochlear,
retrocochlear, central, and tinnitus of unknown cause.

Tinnitus matching. One online tinnitus matcher is found here. Ideally one should match each ear for both loudness and pitch, and use a reproduction device that is calibrated (unlike a computer speaker), and can deliver a full frequency spectrum (unlike most computers).

The audiogram sometimes shows a sensorineural deficit. This may be due to true loss of hearing, or due to masking from the tinnitus.

Tinnitus matching is helpful to identify the frequency and intensity of the tinnitus. This is a simple procedure in which the audiologist adjusts a sound until a patient indicates that it is the same as their tinnitus. Most patients match their tinnitus to the region of their hearing loss (Konig et al, 2006; Mahboubi et al, 2012). Unfortunately, the "gap detection test", does not work to confirm tinnitus in humabs (Boyen et al, 2015).

ABR (ABR) testing may show some subtle abnormalities in otherwise normal persons with tinnitus (Kehrle et al, 2008). The main use of ABR (ABR test) is to assist in diagnosing tinnitus due to a tumor of the 8th nerve or tinnitus due
to a central process. A brain MRI is used for the same general purpose and covers far more territory, but is roughly 3 times more expensive. ABRs are generally not different between patients with tinnitus with or without hyperacusis (Shim et al, 2017).

Tympanograms or acoustic reflex tests can sometimes show a rhythmic compliance change due to a middle ear vascular
mass or due to contraction of muscles in the middle ear.

The physician may also request an OAE test (which is very sensitive to noise induced hearing damage), an ECochG (looking for Meniere's disease and hydrops, an MRI/MRA
test (scan of the brain), a VEMP (looking for damage to other parts of the ear) and several blood tests (ANA, B12, FTA, ESR, SMA-24,
HBA-IC, fasting glucose, TSH, anti-microsomal antibodies).

Neuropsychological testing

There are numerous questionnaires for tinnitus. Some of these are available on our web site (survey.dizzy-doc.com). See this link for more details.

We occasionally recommend neuropsychological testing using a simple screening questionnaire -- depression, anxiety, and OCD (obsessive compulsive disorder) are common in persons with tinnitus. This is not surprising considering how disturbing tinnitus may be to ones life (Holmes and Padgham, 2009). Persons with OCD tend to "obsess" about tinnitus. Treatment of these psychological conditions may be extremely helpful.

Radiological testing of tinnitus

Branstetter and Weissman (2006) reviewed the radiological evaluation of tinnitus. They favor contrast-enhanced MRI to detect tumors of the inner ear area. Of course, tumors are a very rare cause of tinnitus, as tinnitus is at least 100 times more common than tumors of the inner ear area.

Causes that can be seen on radiological testing of continuous tinnitus include: (Branstetter and Weissman)

Tumors of the inner ear area (CPA tumors)

TMJ disease (best seen on CT of the face or temporal bone, or MRI of the joint)

Special tests for pulsatile tinnitus

In persons with pulsatile tinnitus, additional tests maybe proposed to study
the blood vessels and to check the pressure inside the head. Gentle pressure
on the neck can be performed to block the jugular vein but not the carotid artery.
The Valsalva maneuver reduces venous return by increasing intrathoracic pressure.
If there is a venous hum, this usually abates or improves markedly. If the pulsation
is arterial, these tests have no effect.

We this is a big subject and we have split this material to another page on tinnitus treatment. Briefly, the algorithm that we use in our practice to diagnose and treat tinnitus is here (a PDF graphic). After a diagnostic step, there are many branch points involving treatment trials.

Research Studies in Tinnitus

As of 6/2018, a
visit to the National Library of Medicine's search engine, Pubmed,
revealed more than 4,000 research articles with tinnitus in their title, published. In spite of this gigantic effort, very little is presently known about
tinnitus, and effective treatment is generally unavailable.

Plein et al (2015) suggested that the quality of published studies concerning clinical trials for tinnitus were suboptimal, and in fact, only 20% of 147 had a low risk of bias. The author of this page feels happy that at least someone is doing trials on this difficult situation ! Any kind of trial is better than no effort at all.